Chart of the Hour

Discovery Science

About this app

Chart of the Hour draws a tropical birth chart from a date, a time, and a city you pick, then shows where those same bodies are in the sky right now.

The natal screen gives the rising sign and a wheel. For each body it lists the sign, the degree, and the Placidus house. The sky screen gives the current tropical position at that city and the natal house that position is crossing. A house on that screen is only a location on the chart you saved. It is not a prediction.

Bodies: Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, and the mean lunar north node. Zodiac: tropical, of date. Houses: Placidus.

Positions are calculated on the phone. The Sun and planets use Astronomy Engine (truncated VSOP87). The Moon uses that library's lunar theory. The mean north node uses the Meeus polynomial for the mean lunar ascending node. Nothing is fetched over the network to build the chart.

The app is offline. There is no account, no ads, and no analytics. It does not request a network permission or a location permission. Birth date, birth time, and the chosen city stay in local storage on the device. The city list is built in, with a latitude, longitude, and time zone for each city. The app does not read GPS.

There is no horoscope text. Positions only. No fortune, medical, or spiritual claim.

What’s new

First release: offline tropical natal chart with Placidus houses and rising sign.